1. Field of the Invention
This invention relates to hydraulic power systems, and in particular to a hydraulic control system for a variable displacement pump. Still more particularly, the invention pertains to such a control system including an improved load-sensing control valve and an improved cutoff control valve.
2. Description of the Prior Art
A variable displacement pump control system including a load-sensing and a cutoff control valve has been known (FIG. 1 of the accompanying drawings). A problem with this prior art system is that the control valves are of such construction and operation that the displacement of the pump may be varied all the way between 100 and 0 percent in response to slight changes in its output pressure. The result is the instability of the system operation.